The BiobaseTurner package

A data structure for Mathews / Turner RNA and DNA energy
parameters. This library currently only provides an importer,
not export functions. There are two reasons: (i) We currently
have no use-case where we need more than import facilities (ii)
The file structure is geared towards humans, not machines. If
you need to be able to export, send a mail.

NOTE This is rather fragile as some files use different index
enumerations, which we handle rather... simplistically.

In principle, all parameters should be symmetric regarding the
stem direction. However, there is one asymmetry case in
dnastack.dh. We do not fix this problem as we do not change the
source files.